Monitoring anesthesia depth with patient state index during pediatric surgery

Abstract

Background: Monitoring anesthesia depth in children is challenging. Pediatric anesthesiologists estimate general anesthesia depth using indirect methods such as pharmacokinetic models and neurovegetative reflexes. The application of processed electroencephalography may help to identify the correct anesthesia depth (i.e., patient state index between 25 and 50). Aims: To determine the median values of patient state index and spectral edge frequency 95% in children undergoing general anesthesia conducted according to indirect evaluation of depth. The relationships between patient state index and spectral edge frequency 95% and indirect monitoring of anesthesia depth, type of anesthesia, age subgroups, and postoperative delirium were also assessed. Methods: A prospective observational study on children (aged 1–18 years) undergoing surgery longer than 60 min. The SedLine monitor and the novel SedLine pediatric sensors (Masimo Inc., Irvine California) were applied. Patient state index levels were recorded for the duration of the anesthesia until the discharge to the ward at predefined time points. Results: In the 111 enrolled children, median patient state index level at the end of anesthesia induction was 25 (22–32) and ranged from 26 (23–34) to 28 (25–36) in the maintenance phase. Patient state index at extubation was 48 (35–60) and 69 (62–75) at discharge from the operatory room. Median right/left spectral edge frequency 95% values at the end of induction were 10 (6–14)/9 (5–14) Hz and median right/left spectral edge frequency 95% values in the maintenance phase ranged from 10 (6–14) to 12 (11–15) Hz in both hemispheres. At extubation, right/left spectral edge frequency 95% levels were 18 (15–21)/17 (15–21) Hz. We observed 39 episodes of burst suppression in 20 patients (19%). Median patient state index levels were not different between patients undergoing inhalational and intravenous anesthesia and between those undergoing general anesthesia and general anesthesia added to locoregional anesthesia. Children <2 years displayed significantly higher patient state index levels than older patients (p =.0004). The presence of a burst suppression episode was not associated with PAED levels (OR 1.58, 95% CI 0.14–16.74, p` =.18). Conclusions: NonpEEG-guided anesthesia in children led to median patient state index levels at the low range of recommended unconsciousness values with frequent episodes of burst suppression. Patient state index levels were generally higher in children below 2 years.